# Photometric analysis and evolutionary stages of the contact binary V2790 Ori

## TL;DR

This study analyzes the photometric data of the contact binary V2790 Ori, revealing its W-type classification, mass transfer dynamics, and evolutionary changes including mass loss and angular momentum reduction over time.

## Contribution

It provides the first detailed photometric analysis and evolutionary assessment of V2790 Ori, including fundamental parameters and mass transfer rates.

## Key findings

- V2790 Ori is a W-type contact binary with a high mass ratio of 2.932.
- The orbital period is increasing at a rate of 1.03×10^{-7} days per year.
- Significant mass transfer and loss have occurred, affecting the system's evolution.

## Abstract

A photometric analysis and evolutionary stages of the contact binary V2790~Ori is presented. The $BVR_\mathrm{C}$ observations were carried out at the Thai National Observatory. The photometric light curves were fitted to provide fundamental parameters, required to use in the analysis of evolutionary stages of the binary. The results show that V2790~Ori is a W-type contact system with a mass ratio of $q$~=~2.932. The orbital period increase is found at a rate of $\mathrm{d}P\slash \mathrm{d}t~=~$1.03$\times10^{-7}~$d~yr$^{-1}$. It implies that a rate of mass transfer from the secondary component to the primary one is $\mathrm{d}m_2\slash \mathrm{d}t~=~$6.31$\times10^{-8}~M_{\odot}$~yr$^{-1}$. Furthermore, we find that from the detached phase to the contact phase, mass of the evolved secondary component has been lost 1.188$\pm$0.110~$\mathrm{M}_{\odot}$, i.e., mass lost by the system of 0.789$\pm$0.073~$\mathrm{M}_{\odot}$ and mass transfer to the primary of 0.399$\pm$0.037~$\mathrm{M}_{\odot}$. Since the time of the first overflow, the angular momentum loss is found to be 72.2~$\%$ of $J_\mathrm{FOF}$, causing the orbit and Roche surface to shrink until the present time.